Organic ultraviolet (UV) filters have been widely incorporated on sunscreens as the main ingredient to absorb UV-rays from solar radiation. Among organic UV filters, benzophenone-3 (BP3, oxybenzone) has been extensively applied on sunscreens as well as into thousands of products ranging from pharmaceutical, pesticides, plastics stabilizer, paints, textiles and personal-care products such as cosmetics, shampoos, fragrances, and detergents which are consumed daily worldwide. Sunscreens are used in increasing amounts; due to growing concerns in reduce skin maladies (e.g. sunburns and skin cancer) by absorbing UV radiations ranging between UVB (315-280 nm) and UVA (400-315 nm). The extensive consumption of sunscreens around the world is mostly associated to coastal tourism activities (e.g. beachgoers).
A series of studies reported that BP3 enters environmental waters, after sunscreens were scrubbed-out from beachgoers skin are defined as a direct input of BP3 onto recreational water systems was observed at coastal waters, rivers, swimming pools and lakes. Furthermore, the relationship between higher BP3 concentrations on coastal waters as a function of number of beachgoers on various tropical beaches has been correlated. It has also been reported that the levels of BP3 range between (75 ug/L-1.4 mg/L) and (0.8 ug/L-19.2 ug/L) in seawater sampled throughout U.S. Virgin Islands and Hawaii's islands, respectively.
BP3 contamination in aquatic systems was promulgated as an emerging contaminant of growing concerns for their endocrine disrupting properties on marine organisms. Prior art reported the first studies on the effects of BP3 concentration on bleached corals under in-vitro experimental parameters showing BP3 concentrations ranging from 2.3 ug/L to 2 mg/L on coral bleached. Several in vitro studies further supports that even trace amounts of BP3 has been linked to coral bleaching. Among others assays closely agreement was observed to weaken immune systems of corals as well as disrupting symbiotic properties. Furthermore, insight in-vitro studies reveal adverse effects of BP3 endocrine disrupting functions on certain fish species. The use of BP3 active ingredients in sunscreens will increase at unprecedented levels in the coming decades. It has been estimated that 16,000 tons of BP3 are expected to be discharged from coastal tourism throughout the Caribbean by the year 2020. Therefore, special attention should be given when considering the reduction of BP3 directly discharged into coastal waters for the remediation of coral reefs and marine habitats along touristic hotspots beaches within the Caribbean islands.
Currently, conventional wastewater techniques for the removal of BP3 have been broadly applied on diverse treatment procedures. Although the efficiency of coagulation-flocculation removal procedures for BP3 were reported on less than 10%, studies have shown that these are inadequate procedures for the removal of BP3. A wastewater treatment plant with continuous a microfiltration process only achieves removal (>5%) of BP3. However, many studies were carried out on wastewater treatment plants with advanced oxidation processes (AOP), like ozonation, where efficiencies removal of BP3 were reported ranging from 20, 28, and 43%. In addition to ozonation, other studies of advanced oxidation processes, such as ultrasonic irradiation were used to remove 67% of BP3 from aqueous solutions. The operational costs as well as maintenance complexes procedures including the by-product residues are limited to few wastewater treatment plants. A previous report showed that ˜84% was removed by adsorption of BP3 onto powder activated granular carbon adsorbent from aqueous solutions. Despite numerous conventional and advanced methods being available to remove BP3 in wastewater treatment plants, these procedures cannot be directly integrated onto coastal waters polluted by marine tourism activities. Currently, in-situ remediation techniques for BP3 removal from coastal waters, by means of adsorption procedures, have not been reported on the literature.